Timing switch



L. ROSE TIMING SWITCH Feb. 6, 1968 5 Sheets-Sheet 1 Filed Oct. 23, 1965726/ Zfs 7% INVENTOR. LEONARD ROSE jam 1% A.

ATTORNEY Feb. 6, 1968 L. ROSE 3,367,193

. TIMING SWITCH Filed Oct 23, 1965 5 Sheets-Sheet 2 INVENTOR. LEONARDROSE fimw/ a;

ATTOR EY Feb. 6, 1968 L. ROSE 3,367,193 TIMING SWITCH I Filed Oct. 23,1965 3 Sheets-Sheet 5 LEONARD ROSE ATTORNEY United States Patent3,367,193 THVIING SWITCH Leonard Rose, Wantagh, N.Y., assignor toConsolidated Airborne Systems, Inc, New Hyde Park, N.Y. Filed Oct. 23,1965, Ser. No. 502,941 Claims. (Cl. 74--3.5)

ABSTRACT OF THE DISCLOSURE Precision timing device employing a pluralityof individually adjustable cams on a common motor-driven shaft. Aselected cam triggers a switch controlling linkage.

This invention relates to switches in general and more particularly to atiming switch having a plurality of individually selectable timeintervals of different predetermined durations.

While the present invention has utility in many different fields, thedescription will be directed particularly to the use of a timing switchin a microwave oven. In that particular application, it is necessary toprovide a simple and easily operated switch that has a number ofdifferent preset time intervals which the user may select in order tomeet various cooking requirements.

A typical use for a microwave oven is in connection with refrigeratedvending machines. The customer purchases an item from the vendingmachine and then cooks it himself. It is essential that the instructionsto the customer be simple. Typically, the instructions may read: To cookthis food item, (a) open the oven door; (b) insert merchandise; (c)close the oven door; and (at) press button No. 5. In order for theautomatic vending installation to be practical, the pressing of thebutton must turn on the oven and also initiate an accurate, reliabletiming mechanism. Because a variety of items of different nature arelikely to be vended from a single machine. a range of cooking times mustbe provided. Further, since the cooking cycle is so short in a microwaveoven, being measured in seconds, the timing mechanism must be reasonablyaccurate. It is also important, in order for the vending operation to becommercially feasible, that the switch be compact, relatively low incost, and capable of a long maintenance-free life. As will be evidentfrom the ensuing description, the timing switch of this inventionsatisfies all these requirements.

The timer of this invention allows the presetting of six different timeintervals and then permits selection of a contact closing time when oneof six buttons is engaged. After the interval passes, the timerautomatically and instantaneously resets itself whereby it is ready foranother time selection.

This device is extremely useful where a number of different fixedintervals are to be repeated. The timer is characterized by lightweightand compact and rugged construction, and is capable of operation underthe most adverse conditions such as a greasy atmosphere.

The timer consists of a synchronous speed motor which is mechanicallycoupled to a cam shaft when any button is engaged. Six cams arepre-arranged on this shaft, the angular position of each camrepresenting a unique time interval. Any interval from five seconds tothree minutes can be set into the timer by angular adjustment of thecam. This is simply and quickly done by a drive mechanism on the cam.The mechanism is self-locking so that while the cam is easily positionedthrough a screw drive slot accessible in the front of the timer, theaction of the cam against the latching bar will not cause the cam tomove.

The pushing in of a button accomplishes the following functions:

(1) It couples the cam shaft to the motor to start the cams rotating;

(2) It closes a set of contacts in an enclosed snap action switch; and

(3) It selects the cam which represents the desired time interval.

When the time elapses, the cam releases the engaged arm, which in turnopens the switch contacts and declutches the cam shaft from the motor. Atorque spring returns the cam shaft to its starting position, resettingthe timer and allowing another timer cycle to be selected.

Accordingly, it is an object of the present invention to provide a lowcost, maintenance-free timing switch hav ing a selectable plurality ofdifferent time durations.

Another object is to provide an accurate timing switch of theaforementioned type.

A further object is to provide a timing switch wherein the timeintervals may be readily and accurately set and/ or changed byauthorized personnel.

Yet another object is to provide a timing switch of a size suitable forinstallation in a relatively small size microwave oven.

An additional object is to provide adjustable self-locking timing earns.

These and other features, objects and advantages of the invention will,in part, be pointed out with particularity and will, in part, becomeobvious from the following more detailed description of the invention,taken in conjunction with the accompanying drawing, which forms anintegral part thereof.

In the various figures of the drawing like reference charactersdesignate like parts.-

In the drawing:

FIG. 1 is a front elevational view of the timing switch comprising thepresent invention;

FIG. 2 is a bottom plan view of the present invention;

FIG. 3 is an end elevational view as seen from the lefthand side of FIG.1;

FIG. 4 is a detailed plan view of several components of the presentinvention;

FIG. 5 is a fragmentary transverse elevational view, in section,illustrating the relationship of the cams used therein;

FIG. 6 is a fragmentary bottom plan view of the motorized drive section;

FIG. 7 is a fragmentary sectional detail view illustrating means tomount a typical combination cam and gear;

FIGS. 8, 9 and 10 sequentially illustrate in transverse elevationalviews the position of various components at different times of a typicaltiming cycle;

FIG. 11 is a perspective view of a stop member used with this invention;and

FIG. 12 is a sectional elevational view taken along line 1212 of FIG.11.

Referring now to FIGS. 1, 2 and 3 of the drawing, it will be seen thatswitch 20 includes a chassis comprised of front and rear plates 22 and24 and end plates 26 and 28 secured to inwardly turned flanges of thefront and rear plates. A mounting bracket 30 is secured to end plate 26and serves to support a synchronous timing motor 32. A one-third r.p.m.synchronous motor has been found to be satisfactory. Motor shaft 34extends through the mounting bracket and supports a driving clutch plate36 that is biased into an operating position by means of a compressionspring 38.

Transverse cam shaft 40, having a square cross sectional central portionand cylindrical ends, is rotatably journaled in the chassis end platesin opposition to the motor shaft;

Shaft 40 rigidly supports a driven clutch plate 42 proximate the drivingclutch plate 36. Mounted on the cam shaft intermediate the end walls ofthe chassis are, in the embodiment illustrated, six timing gears 44a'to44f in- Patented Feb. 6, 1968 clusive. By way of example, the gears maybe fabricated from nylon and include an integral lobe 46a to 46f,respectively, extending radially from the periphery thereof. In theembodiment illustrated, the gear is a lefthanded face worm gear having39 teeth. It is to be understood, of course, that this is by way ofillustration only and without intending to be limiting.

Referring now particularly to FIG. 7, a typical gear is shown mounted onhub member 48. Each gear, of course, has its own individual hub. Thegear is free to rotate angularly but is prevented from axial movementrelative to the'hub by means of a step 50 formed in the hub and arrangedto bear against the transverse gear web and a retaining ring 52 securedto the hub. Mating worm pinions 54a to 54f are rotatably secured to, andretained within, an extension portion 56 on each of the hub members. The

advantage of the face worm gear and pinion set is that it isself-locking after adjustment-Each pinion is provided with a slotted endthat faces the front of the housing, so that it is available foradjustment through cutout 22a in the chassis front plate. Thecombination gear and cam assemblies are keyed to the shaft by means ofthe square shaft configuration and square bore provided in each hubmember. Thus, a finite relation among the cams may be established.

At the end of the cam shaft opposite to the clutch assembly there isprovided a stop member 8 (FIG. 11 and FIG. 12) arranged for rotationwith the cam shaft. The stop member is provided with two spaced parallellegs 60a-and 60b, each'having square-shaped coaxial bores 62 permittingthe stop member to be keyed to the cam shaftnFurther, leg 60a isprovided with a tab portion 64 arranged to abut a resiliently converedpost 66 secured to and extending inwardly from end plate 28. Stop member58 limits the angular movement of the cam shaft to slightly less than360. As will be described hereinafter, when the motor is running and theclutch plates are engaged, the stop member turns with the shaft. Whenthe time cycle is completed and the clutch plates disengaged, it isdesired to bring the stop member, the cams and the cam shaft back to itsoriginal starting position. Accordingly, a coiled clock-type spring 68is mounted on the outside of plate 28. The inner end of the spring issecured to the lefthand end of the transverse cam shaft 40, and theopposite end of the spring is secured to the outward extension of post66. The spring is wound up as the cam shaft rotates during the timinginterval and unwinds to return the components to the starting positionas determined by the stop member 58 engaging post 66.

Externally positioned pushbuttons 70a to 70 are each secured to one endof slide bars 72a to 72f, respectively, which are journaled in front andrear chassis plates 22 and 24. Each slide bar is a substantially flatmember having stepped portion 74. One end of compression spring 76 isseated against the stepped portion and the opposite end of the springabuts the inner surface of plate 24. Thus means. are provided forreturning the selected pushbutton to its original outward position afterthe respective time interval has passed. Each slide bar is also providedwith a first camming follower 78 integral with its upper edge, a slopingsecond camming follower 80 integral with its lower edge, and a thirdU-shaped camming follower 82 pivotally mounted on a pin 83 disposed inthe body portion of the slide bar. Follower 82 is defined by an upperleg 84a positioned above the slide bar and a lower leg 84b positionedbelow the slide bar. Torsion spring 85 is disposed about pin 83 andextends between the upper edge of slide bar 72 and the lower leg 84b ofthe third cam follower. v

A clutch bar 86 (FIG. 4)- is a substantially flat plate, having sixnotches defined by a sloped camming wall 90a to 90p and walls 90a to 91)disposed in a plane parallel to the slide bar. Each notch correspondsrespectively to a pushbutton, to a slide bar and to a cam/ gearassembly. The clutclf bar is mounted in the end plates of the housing 1is complete. The opposite end of the clutch bar is bent upwardly in aplane substantially at right angles to the main portion of the bar andterminates in a yoke portion 94. Bushing 96, which is secured to thetransverse cam shaft, has an annular groove 98 arrangedto receive theyoke. Therefore, displacement of the clutch bar by the pushbutton andslide bar causes axial displacementof'the cam shaft and engagement ofthe two clutch plates.

Latching bar 100 is pivotally journaled along onelongitudinal edge onpins 102 in the end plates 26 and 28 of the chassis. The latching barlies in a plane parallel to the clutch bar and directly below the slidebars.

When a pushbutton is depressed, its associated follower overrides thefree end of the latching bar which is proivded with a lip portion 104extendingalong the longitudinal edge thereof opposite to the pivotingedge. Follower 80, because of its angularly-disposed contacting surface,tends to pivot the latching bar when it is moved thereover and alsolooks step 81 against lip 104.,A single, snap action switch 106 ismounted on plate 28 such that its contact button 108 faces upwardly andis in normal engagement with latching bar 100. Pivoting of the latchingbar causes depression of the contact button and energization of theutilization device.

MODE OF OPERATION Assuming that the product to be cooked requires 15seconds, the user would depress button No. 2. In so doing cammingfollower 78 would engage the angularly disposed edge of the associatednotch in the clutch bar. The inward movement of the pushbutton and slidebar will displace the clutch bar to the right, causing yoke member 94 toshift the driven clutch face 42 into engagement with the driving clutchplate 36 of the motor. It should be noted, of course, that it is onlywhen the motor is running and the clutch plates are in engagement, thatthe transverse shaft will be rotated thereby. The depression of theparticular pushbutton will also cause the second follower surface toengage the latching bar. Thus a single pushbutton motion willsimultaneously energize the switch and actuate the cam shaft through themotor.

Concurrently with the depression. of the switch, the

fluence of the motor. It should be pointed out now that, theangularlocation of the cam lobe is determined by adjustment of the gear throughthe pinion. Knowing the rotational speed of the motor, it is a simplestep to angularly position the cam lobe 46 by rotating the slottedpinion 54 such that the time it takes the lobe to travel from itsstarting point to engagement with third follower leg 84 is equal to thedesired time interval. When the lobe engages third follower leg 84a, thefollower 82 is pivoted against the force of torsion spring 85. Thepivoting action causes leg 84b to bear against depressed lip 104 oflatching bar such that follower 80 is thereby released. Spring 76returns the pushbutton to its outer position. and spring 92 returns theclutch bar 86 to its original position. With the return of the latchingbar, the clutch faces are disengaged and spring 68 returns thetransverse shaft to its original starting position. The apparatusis nowavailable for a second cycle.

FIG. 9 illustrates one particular application of the present invention.Closing of the switch contacts completes the circuit between the motor32, the utilization.

also initiates the timing cycle. Since each pushbutton has its ownadjustable cam, the timing cycle may be very accurately terminated.

The apparatus just described is com-pact, low in cost and sufiicientlyaccurate to meet the requirements of a microwave oven, for example. Asingle operation starts both the timer and the oven so that instructionsfor the use of the device may be given in the very simplest of terms.The apparatus may be operated for any one of a number of predeterminedtime intervals so that many cooking requirements will be satisfied. Inaddition, means are provided permitting authorized personnel to readilyand accurately set or change the various time intervals available.

Having thus disclosed the best embodiment of the invention presentlycontemplated, it is to be understood that various changes andmodifications may be made by those skilled in the art without departingfrom the spirit of the invention.

What is claimed is:

1. In combination with a switch, selectable time interval switchactuation means comprising:

(a) a plurality of pushbuttons each related to a given predeterminedtime interval;

(b) interposer means for mechanically placing the switch means in anactuated condition;

(c) a latching means connected to each of said pushbuttons, saidlatching means being normally positioned in spaced relationship to saidinterposer means whereby when a given said pushbutton is depressed, itsassociated said latching means engages said interposer means; and

(d) means for automatically deactuating said switch and returning saiddepressed pushbutton to its initial position upon the completion of thetime interval.

2. An actuating mechanism for a utilization device having a plurality ofoperating cycles of different time duration, said actuating mechanismcomprising:

(a) a chassis;

(b) a plurality of externally manipulatable slide bars movably mountedin said chassis said slide bars having first and second cammingsurfaces;

(0) a cam shaft having a first clutch face coupled to said cam shafthaving end portions rotatably journaled in said chassis, the axis ofsaid shaft being transverse the direction of movement of said slidebars;

(d) a plurality of cams mounted on said shaft for rotation therewith,each of said cams having a lobe in operative association with one ofsaid slide bars;

(e) a drive motor and a drive motor shaft driven thereby mounted on saidchassis;

(f) a second clutch face carried by said drive motor shaft;

(g) a clutch bar slidably mounted in said chassis for movement in adirection parallel to the axis of said cam shaft, said clutch bar beingin engagement with said cam shaft and positioned for engagement by thesaid slide bar first camming surface of a selected slide bar wherebysaid clutch bar is displaced and said first and second clutch faces areengaged;

(h) a latching bar pivotally mounted in said chassis, said latching barbeing positioned for engagement by the said second camming surface of aselected said slide bar for displacement about an axis parallel to saidcam shaft by the movement of any one of said slide bars, said latchingbar being returned to its original position by the rotation and contactof said cam lobe with a third camming surface on said slide bar; and

(i) utilization device control means positioned proximate said latchingbar and arranged for actuation thereby responsive to the movementthereof.

3. The apparatus in accordance with claim 2 including adjustment meansto vary the angular location of the cam lobes with respect to eachother.

4. The apparatus in accordance with claim 2 including a plurality of hubmembers mounted on said cam shaft for rotation therewith, a gear memberintegral with each of said cams, said gear members being axiallyrestrained in said respective hub member and arranged for angulardisplacement with respect thereto, and a pinion rotatably mounted ineach of said hub members and in meshing engagement with a respectivesaid gear, adjustment means being included on each pinion for angulardisplacement thereof whereby each of said gears, said cams, and said camlobes maybe angularly displaced.

5. The apparatus in accordance with claim 2 wherein said third cammingsurface is pivotally mounted on and resiliently biased with respect tosaid slide bar.

6. The apparatus in accordance with claim 4 wherein said hub members arekeyed to said cam shaft.

7. The apparatus in accordance with claim 4 wherein the central portionof said cam shaft has a noncircular cross section and said hub membereach have a mating aperture of similar shape whereby said hub membersare keyed to said cam shaft.

8. The apparatus in accordance with claim 2 wherein said clutch barincludes a body portion having a plurality of notches along one edgethereof, each of said notches having a sloping wall in the path of saidrespective first camming means whereby movement of said slide bars in adirection transverse the length of said clutch bar will provide acamming action to thereby displace said clutch bar body portion, saidclutch bar further including a leg member integrally joined at one endto said body portion, the opposite end of said leg member terminating ina yoke arranged to engage and displace said cam shaft upon movement ofone of said slide bars.

9. The apparatus in accordance with claim 2 wherein said latching barincludes a lip portion extending along one edge thereof whereby movementof one of said slide bars in a direction transverse the length of saidlatching bar causes a portion of said second camming means to hook ontosaid lip whereby said slide bar is retained in the position to which ithas been moved.

10. The apparatus in accordance with claim 2 including stop meansintegrally mounted on said cam shaft for rotation therewith, saidchassis including a post member arranged to limit the rotation of saidstop member at either end of the angular travel thereof, there beingfurther included spring means arranged to return said cam shaft to itsoriginal position after completion of a time interval during which saidcam shaft has rotated from one extreme position to another.

References Cited UNITED STATES PATENTS 3,015,003 12/1961 Simmons 74--3.5X

MILTON KAUFMAN, Primary Examiner.

